Could the language we speak skew our financial decision-making, and does the fact that you're reading this in English make you less likely than a Mandarin speaker to save for your old age?

It is a controversial theory which has been given some weight by new findings from a Yale University behavioural economist, Keith Chen.

Prof Chen says his research proves that the grammar of the language we speak affects both our finances and our health.

Bluntly, he says, if you speak English you are likely to save less for your old age, smoke more and get less exercise than if you speak a language like Mandarin, Yoruba or Malay.

Future-speak

Prof Chen divides the world's languages into two groups, depending on how they treat the concept of time.

Strong future-time reference languages (strong FTR) require their speakers to use a different tense when speaking of the future. Weak future-time reference (weak FTR) languages do not.

"If I wanted to explain to an English-speaking colleague why I can't attend a meeting later today, I could not say 'I go to a seminar', English grammar would oblige me to say 'I will go, am going, or have to go to a seminar'.

"If, on the other hand, I were speaking Mandarin, it would be quite natural for me to omit any marker of future time and say 'I go listen seminar' since the context leaves little room for misunderstanding," says Prof Chen.

Even within European languages there are clear grammatical differences in the way they treat future events, he says.

"In English you have to say 'it will rain tomorrow' while in German you can say 'morgen regnet es' - it rains tomorrow."

Disassociating the future

Speakers of languages which only use the present tense when dealing with the future are likely to save more money than those who speak languages which require the use a future tense, he argues.

So how does a mere difference in grammar cause people to save less for their retirement?

"The act of savings is fundamentally about understanding that your future self - the person you're saving for - is in some sense equivalent to your present self," Prof Chen told the BBC's Business Daily.

"If your language separates the future and the present in its grammar that seems to lead you to slightly disassociate the future from the present every time you speak.

"That effectively makes it harder for you to save."

Even more controversial, is Prof Chen's assertion that language differences underpin wider differences in people's behaviour.

In his research paper, he says that compared to speakers of languages which use a future tense, speakers of languages with no real future tense are:

Likely to have saved 39% more by the time they retire
31% more likely to save in a year
24% less likely to smoke
29% more likely to be physically active
13% less likely to be obese

Far-fetched?

Not surprisingly, Prof Chen's findings have been criticised by both economists and linguists.

They argue there are number of cultural, social, or economic reasons why different language speakers behave differently.

It is a point Prof Chen acknowledges, saying "I completely agree, it seemed far-fetched to me when I started doing this research as well."

But he says his research has controlled for all these factors, by concentrating on nine multi-lingual countries: Belgium, Burkina Faso, Ethiopia, Estonia, DR Congo, Nigeria, Malaysia, Singapore, and Switzerland.

"You can find families that live right next door to each other, have exactly the same education levels, exactly the same income and even exactly same religion.

"Yet the family that speaks a language that doesn't distinguish between the future and the present will save dramatically more," he says.

In Nigeria, for example, Hausa has multiple future tenses, while Yoruba does not.

"You can find Nigerians who speak Hausa and Yoruba who live next to each other and yet have radically different savings behaviour."

Findings challenged

But Morten Lau, director of Durham University's Centre for Behavioural Economics, says the factors which affect how much people save have little to do with language.

"In my own work with savings, it is interest rates that determine savings behaviour."

Prof Lau says there are often significant differences within language groups, and just using the average of these results in analysis can prove problematic.

"You have to be careful the inferences you make from correlations like these. It is very difficult to control for multiple factors."

"For instance, in our own research in Denmark, we found that male smokers wanted a higher interest rate on their savings than did non-smokers. But that this did not apply to women smokers."

'A tempting idea'

Linguist John McWhorter, of Columbia University, says any influence a language's structure has on the way its speakers see their world is extremely subtle.

"The extent to which the language shapes the thought is tiny. We're talking about milliseconds of reaction.

"None of it has ever been proven to have anything to do with how people see the world or experience life.

"It's a tempting idea that simply doesn't make any sense."

Also, he says, some languages have been wrongly classified, thus undermining the statistical correlations.

"Russian, and languages like it, are a lot more like Mandarin than Keith Chen thinks."

Despite his critics, Prof Chen insists his findings are robust.

"What's remarkable, is when you find correlations this strong and that survive so many aggressive sets of controls, it's actually hard to come up with a story of what else might be causing this."

So what does Prof Chen think of the idea that if he is right, then English speakers who want to start saving more for their retirement, should talking entirely in the present tense?

"It actually seems like encouraging yourself to think in the present tense makes it a little bit easier to engage in self-control."